Sit up exercise machine



FIG. 1 is a perspective view showing the design of my invention.

FIG. 2 is a elevational view of from the right side.

FIG. 3 is an elevational view of from the left side.

FIG. 4 is a front elevational view.

FIG. 5 is a rear elevational view.

FIG. 6 is a top plan view; and,

FIG. 7 is bottom plan view. 

The ornamental design for a sit up exercise machine, as shown and described. 